Eric Adams responded to Mr Khan’s £10m campaign to win back the three million US tourists a year who visited London pre-pandemic with an appeal to Londoners to visit the Big Apple.
The London tourism campaign was formally unveiled at Times Square, in the heart of New York’s Broadway theatre district, on Monday morning.
Hundreds of New Yorkers stopped to watch a showcase of the capital featuring three Grenadier Guards, a vintage black taxi, red phone boxes and a performance by stars from Six The Musical, which is currently showing both on Broadway and the West End.
Ahead of the launch, after a 30-minute meeting with Mr Khan at New York City Hall, Mr Adams told reporters: “He and I are going to be in friendly competition.
“We get many mayors in this city. Every week there is a new mayor here. But there was a bit of energy with you coming here.
“Among the mayors, you are like the rock star of mayors. People were excited, my team was excited to see you and see what you’re doing.”
He hailed Mr Khan, who last year became chairman of the C40 group of world cities committed to implementing measures to tackle climate change, as a “visionary” and “a person that many of us look up to”.
Mr Adams said New York and London had both gone through the “traumatic” experience of the pandemic and the economic collapse that it caused.
More than 40,000 New Yorkers have died with Covid, mask-wearing rules remain in force and Covid testing booths are on every main avenue in Manhattan.
Mr Adams defended himself against criticism for a visit to Los Angeles that resulted in his delayed return to New York.
It came as Mr Khan started to face questions from the GLA Conservatives about the cost of his five-day tourism and trade mission to the US, and how he selected the business people who will join the trip when it reaches California on Monday night.
Neil Garratt, a Tory member of the London Assembly, tweeted: Remind me, is this a trip for the Mayor to promote London or to promote himself?”
Mr Garratt said he had already submitted written questions asking how much the trip was costing, who was paging and how the delegates were selected.
Mr Adams, in a rebuke to his critics that also offered appeared to defend Mr Khan, said: “If you are a mayor who only stands on your block, you are not going to solve the problems of the globe. We better start thinking globally if we want to solve global problems.
“The fact that we have this amazing mayor from London who gets it. What he learns here, he is going to take back to his city, and use it to lift up his city. I’m really happy to be here with an international-thinking mayor, Mayor Khan.”